A SEPTA cop wrestled on the ground with a suspect who later died as panicked dispatchers and cops tried to figure out where he was for eight minutes, audio recordings played for the media showed.

But authoriites are still investigating what, exactly, led to the man's death after he was transported to a local hospital and why it took 10 minutes for police to drive him to the hospital after he was finally handcuffed. 

The incident happened at the Huntington Station on the Market-Frankford Line sometime before 2 a.m. as a transit cop was closing the station. 

Video shows the officer escorting the man, apparently peacefully, out of the station to the street level, where he gets into an argument with a third person. 

After the officer breaks up that argument, the man — who has yet to be identified by police — turns his anger on the officer. 

According to police radio traffic, the officer called for backup at 1:56 a.m. He did not tell other dispatchers where he was. Dispatchers could be heard in the audio saying he could be anywhere between 2nd Street in Center City to Frankford Avenue. 

"When you are rolling around on the ground," said SEPTA Police Chief Thomas Nestel III, "sometimes you forget the most important thing, and that's where you are." 

RELATED: Video: SEPTA cops investigate fare-dodging arrest.

Nestel said the officer used a stun gun on the suspect. It's not known how many times the stun gun was used, and whether it contributed to the man's death.

Six minutes later, the officer is finally able to give his location. Two minutes after that, backup officers arrive. The man was subdued at 2:05 a.m.

"Eight minutes is a very long time," Nestel said. 

Police say the suspect was concious when he was put into the back of a police car. But when he arrived at Frankford-Aria Hospital at 2:18 a.m., he was unresponsive. 

Nestel said the man still had a pulse, but he was no longer responding to questions from officers. 

It's unclear when the suspect's medical condition changed. Police logs show that after he was handcuffed, police did not leave the scene to transport him until 2:16 a.m. 

RELATED: Watch SEPTA police help a man who has fallen on the tracks.

Nestel said the officer is a five-year veteran of the SEPTA Police Department. He has no prior complaints for the use of excessive force. He generally works the midnight shift, which Nestel said is typically quiet. 

An autopsy is being conducted to determine the man's cause of death.

Detectives from the Philadelphia Police Homicide Unit are working to determine if the officer committed a crime. 

The officer was treated for a bite wound to the wrist.